Once a common sight on Christchurch roadsides, the portable toilet is almost extinct.

At their peak after the February 2011 earthquake, nearly 3000 were in use around the city.

Only 30 are now needed at homes with damaged sewerage - 20 in the red zone and 10 in the green zone.

City council water and waste manager Mark Christison said only people with damage to their pipe network were now without service.

Portable-toilet users in the red zone had decided against using insurance money for temporary repairs to their pipes, and those in the green zone were working with insurers for repairs to pipes on their property, he said.

"For the others, the council has installed tanks on their property, and sucker trucks come around on a regular basis to empty these out," Christison said.

Residents could use all the facilities in their house in a "normal manner", he said.

Burwood woman Chris Yee, a dialysis patient on the kidney transplant waiting list, still needs a portable toilet because of plumbing problems on her green-zoned property.

She used the internal toilet to minimise infection risk but guests and the nurse administering her five-hour dialysis treatments were forced to use the portable toilet on the street.

The plumbing on the property had not functioned fully since February last year. Repairs were still being investigated.

"[The toilet] flushes, but if it overflushes it gets blocked. I have to be really careful because once you go on the transplant list you have to make sure you don't catch anything," Yee said.

The council cleaned the portable toilet twice a week.

Christchurch East Labour MP Lianne Dalziel said she was "incredibly admiring" of the infrastructure repairs that had been completed and the "amazing" workers.